There is a growing concern about the security of dangerous situations such as pickpocketing, robbery, and sex crimes in public places such as downtown, traffic roads, and alleyway parks. As a means for preventing the occurrence of such a dangerous situation, it is possible to provide a service such as a so-called ‘secure home return service’. The secure home return service may include a process of manually or automatically notifying others of the emergency by using a function provided by the mobile wireless terminal when an emergency occurs. In order to automatically notify the emergency situation, the emergency situation should be recognized automatically.
Screaming may occur in an emergency situation. If this scream is able to be distinguished from the sound other than the scream, the emergency situation may be recognized automatically. In order to determine whether a signal acquired by a microphone corresponds to a scream, it is necessary to perform a frequency analysis on the signal. A considerable amount of computation may be required for frequency analysis. Therefore, in a battery-operated device such as a mobile wireless terminal such as a smart phone, when it is determined whether screaming is continued by using the frequency analysis method according to the related art, the use time of the smart phone may be greatly shortened. In this case, even if an application for determining screaming is provided, it may be disregarded by the users.
Therefore, it is necessary to reduce the battery consumption by reducing the calculation amount to recognize the screaming.